Thesis (M.Sc.) - Cairo University - Faculty of Veterinary Medicine - Department of Food Hygiene and Control

Fish are considered as important source of protein, essential minerals, vitamins and unsaturated fatty acids. However, from nutritional and economic point of view, it may be a main source of heavy metals which can counteract their beneficial effects and may cause health hazards for human if consumed for long time.Therefore, eighty fish samples "Mugil cephalus and Clarias lazera" were randomly collected from Kafr- El-sheikh governorate, Egypt. Fish samples were collected from different sources (markets, captures and farms) and were analysed for heavy metals residues (Total Mercury, Lead, Cadmium and Zinc) in their flesh using Atomic Absorption Spectrophotometer (AAS). Fish samples collected from market revealed that the percent of samples exceeded the safe permissible limits for Hg, Pb and Cd that established by EOSQC (2010) were 35, 20 & 20% and 65, 55 &60% for Mugil cephalus and Clarias lazera respectively. Even though, fish samples were collected from capture showed that 30, 20&20% and 50, 40& 60% for Hg, Pb and Cd residues of Mugil cephalus and Clarias lazeraexceeded such safe permissible limits respectively. The results also showed that the percent of farmed fish samples exceeded the safe permissible limits were 30, 0 &10% and 70, 40 & 60% for Hg, Pb and Cd residues of Mugil cephalus and Clarias lazera respectively.The results also clarified that Zn concentration levels of both Mugil cephalus and Clarias lazera fish were higher than those of other examined heavy metals residues. Moreover,there were non- significant differences (p>0.05) in heavy metal concentration levels in flesh of Mugil cephalus and Clarias lazerawhich were collected from captures and farms

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